For machinists using LinuxCNC, Mach4, or GRBL-based controllers, the "Live View Axis Updated" message (or its equivalent like "Pos: X=150.23 Y=75.00 Updated") is vital.
When this message flows smoothly, you have control. You can cut a part to 0.001mm tolerance, track a suspect across a football field, or map a kilometer of coastline. live view axis updated